Toro 31210-ZB8-0130 lawn mower starter motor | 12V 14-tooth | single-cylinder air-cooled

12V replacement starter motor reference for Honda GX340 / GX390 / GX420 single-cylinder air-cooled engines, circulated under the Toro part number 31210-ZB8-0130. The unit is a Denso OSGR gear-reduction starter, also listed under Honda 31210-ZE3-013 and Denso 128000-2750, for construction and commercial equipment.

OEM and Search References

• Primary reference: 31210-ZB8-0130 (Toro channel)
• Substitute reference: Honda 31210-ZE3-013 / 31210-ZE3-0130 / 31210-ZE3-023 / DB5B6 / DB5B8; Denso 128000-2750 / 128000-3400 / 9712809-275; Lester 18513; J&N 410-52044; Cargo 113231; Andre Niermann 019401; Dubois 918513; Dixie S-80101; Haiwei QDY-188
• Equipment reference: Honda GX340 (338cc, 11HP, QAE2 / QNE2 / VXE2) / GX390 (389cc, 13HP) / GX420 (16HP) single-cylinder air-cooled engines; typical equipment: Toro Dingo TX-413 skid-steer loader (2004–2008, 13HP), Vermeer V1150 / V1350, Ditch Witch trenchers, Allmand EZ1100, Bush Hog GT42 / GT48 and similar construction and commercial machines.
• Buyer search terms: Toro 31210-ZB8-0130 starter motor, Honda GX390 starter, GX340 starter motor, Denso OSGR starter, 14 tooth starter, Dingo TX-413 starter, construction equipment starting motor.

Reference Specifications

• System voltage: 12V, as stated in the product title.
• Power: 0.5 kW, reported by compatible replacement listings cross-referenced to 31210-ZB8-0130.
• Pinion: 14 teeth, reported by compatible replacement listings cross-referenced to 31210-ZB8-0130.
• Pinion outer diameter: 32.3 mm (1.272 in); mounting: two M8 × 1.25 threaded holes; structure: Denso OSGR gear-reduction type with integrated solenoid, approx. 2.3 kg.
• Rotation: counterclockwise (CCW, viewed from the pinion end), reported by compatible replacement listings cross-referenced to 31210-ZB8-0130.
• Important identification note: do not confuse this 14-tooth Denso OSGR unit with the 17-tooth Mitsuba starter (31210-ZE1-023) used on Honda GX160. These details are not confirmed Honda / Toro factory specifications; match them against the removed unit before ordering.

Fitment and Purchase Checks

• Catalog-listed equipment: Honda GX340 / GX390 / GX420 engines and the Toro Dingo and construction machines listed above. Confirm machine model and serial number, engine configuration, existing starter number, voltage, pinion tooth count (14 teeth), rotation, mounting type (M8 threaded holes), terminal layout, and physical dimensions before purchase. Exact 31210-ZB8-0130 length, width, and height have not been verified and are omitted.

For Agricultural Buyers and Distributors

• This listing is organized for construction and outdoor power equipment procurement teams, repair shops, and parts distributors searching by equipment model and OEM reference. The same unit carries Honda, Denso, and Toro numbers, selling into both the construction-equipment and lawn-and-garden markets.For quotation, specify the machine model, engine details, old-part number, required quantity, and destination. Confirm price, stock, package quantity, and delivery terms with the seller before placing a purchase order.

Product Positioning

Honda GX340 / GX390 engines power Toro Dingo TX-413 skid-steer loaders, Vermeer trenchers, Ditch Witch units and a wide range of construction and commercial machines that start and stop dozens of times per working day, and the starter is among the first electrical parts to wear out under that duty cycle. When it fails, the machine sits idle while the owner sorts through three part numbers (Honda, Denso, Toro) for the same unit. This starter carries all three reference channels and reproduces the original 14-tooth pinion, threaded mounting pattern and terminal position exactly, so a workshop replaces the unit as a whole and moves on. For parts distributors, one SKU serves both the construction-equipment market and the lawn-and-garden market, and stocking it next to the 17-tooth 31210-ZE1-023 covers the GX-family range with clear separation between the two.

How It Works: Power and Engagement

The unit is a Denso OSGR gear-reduction starter: an internal gear train steps the high-speed armature down to the pinion, multiplying torque so a 0.5 kW motor can crank a 389 cc engine without heavy battery draw. Turning the key energizes the integrated solenoid first, sliding the 14-tooth pinion into mesh with the flywheel ring gear before the main contacts close and apply full battery voltage - the two-step sequence that prevents tooth-on-tooth grinding. Rotation is counter-clockwise viewed from the pinion end, matching the GX flywheel. The two M8 x 1.25 threaded mounting holes locate the pinion-to-ring-gear clearance exactly as the factory unit did, which keeps engagement quiet and complete.

Materials and Durability

• Pinion: hardened steel with a ground tooth profile, resisting the tooth-thinning wear common on high-hour starters.
• Reduction gears: hardened steel internal train, running in sealed grease pockets that keep construction-site dust out.
• Windings: copper wire for low resistance and good heat rejection during repeated start cycles.
• Solenoid: integrated and sealed against dust and water splash, sized for the frequent cranking of commercial duty.
• Housing: coated shell that withstands rain, mud, and the wash-down exposure typical of construction and grounds equipment.

Problems It Solves

Dingo and GX-powered machines usually arrive at the shop with one of four complaints. First, slow cranking that worsens when the engine is hot, caused by weak brush contact or dragging magnets inside the worn original. Second, a grinding or slipping noise from pinion teeth that no longer mesh fully with the ring gear. Third, intermittent no-start from arced or contaminated commutator surfaces. Fourth, a single click with no cranking from burned solenoid contacts. Replacing the complete starter clears all four in one step instead of chasing parts inside a worn unit. One caution before ordering: do not confuse this 14-tooth Denso OSGR unit with the 17-tooth Mitsuba starter (31210-ZE1-023) used on Honda GX160 - count the teeth on the removed pinion before you buy.

Replacement Value for Shops and Distributors

For repair shops, one correctly matched starter returns the machine to work the same day, with no drilling, tapping, or wiring changes in between. For dealers and distributors, the numbers work: 50-unit minimum order, 7-30 day lead time, 12-month warranty, and unit pricing well below OEM supply channels, leaving room for margin at a competitive shelf price. Production follows ISO 9001, IATF 16949, and CE practices, and consistent cross-references to Honda 31210-ZE3-013, Denso 128000-2750, and Lester 18513 keep ordering by catalog number straightforward and returns low.